DISPERSION OF POLLUTION IN A WAVE ENVIRONMENT

Resumen

This paper concerns the wave-induced mixing of a discharged contaminant, and presents the results of a two-part laboratory investigation in which both a twodimensional and a three-dimensional jet were discharged beneath a series of progressive gravity waves. In each case the measured data is compared to an identical discharge in a quiescent ambient. This comparison suggests that the oscillatory wave motion generates a region of intense fluid mixing which cannot be predicted by the existing integral solutions. Comparisons with a Lagrangian model, first proposed by Chin (1988), highlights the importance of the "apparent" mixing associated with the wave-induced deflection of the jet-axis. This provides a convincing explanation for both the non-Gaussian distributions observed by Sharp (1986), and the multi-stage structure of the centre-line decay (Chyan et al., 1991). Furthermore, quantitative comparisons with the Lagrangian model suggest that in addition to the wave-induced deflection, the oscillatory motion produces a significant increase in the rate at which ambient fluid is entrained into the emerging jet.